The present invention relates to an implant, particularly a percutaneous ostomy implant, and a surgical method, which may use that implant, preferably for creating a continent reservoir in communication with a percutaneous port.
Ileostomy and colostomy are common operations which may be necessitated, for example, by malignancy or chronic bowel inflammation. The surgery is called an ileostomy if the colon and rectum are removed and a colostomy if the rectum alone is removed. Similarly an abdominal urostomy is created when the urinary bladder has to be removed due to, for example, bladder cancer. In these operations, a stoma is formed in the abdominal wall to which a bowel segment is connected.
Ostomy is a generic term for any such procedure where a stoma is created.
The stoma, in most cases, has to be connected to a bag for the collection of bodily waste. However, instead of a conventional ileostomy, it is possible to make a reservoir known as a “Kock pouch” from the distal part of the ileum. The pouch is formed in such a way that a nipple valve is created which serves to close the reservoir, whilst allowing it to be drained intermittently by means of a catheter. This is an example of a so-called continent ileostomy (CI) and it was formerly an attractive alternative to conventional ileostomy but is now rarely used. The complexity of the procedure and the high potential for complications—most of them related to dysfunction of the continence nipple valve—has deterred many surgeons from adopting the operation today.
The ileopouch anal anastomosis (IPAA) is today the gold standard worldwide for these patients but, as with a CI, this operation is also risky and failures are common, mostly leading to pouch excision with loss of bowel. Conversion of a failed IPAA to a CI would be a preferable option but, again, surgeons are reluctant to perform this complex and unreliable technique. Likewise, conversion of a malfunctional orthotopic neobladder or Bricker urostomy would be desirable.
In its earlier patent application EP 1632201 A1, the present applicant disclosed a percutaneous ostomy implant comprising a solid-walled cylindrical body and an anchoring section in the form of a circular flange. The device was designed to be implanted through the abdominal wall and secured by an anchoring section located below the fascia, above the muscle layer. This section comprised inner and outer concentric rings interconnected by S-shaped members in order to provide an axially resilient structure which could absorb shear stresses and consequently reduce the risk of tissue damage. Spaces around the S-shaped members and the provision of numerous apertures in the rings allowed for tissue ingrowth and vascularisation. It was proposed to connect the device to the side of the bowel wall and by providing a removable lid on the cylindrical body a continent ostomy could be provided.
U.S. Pat. No. 6,017,355 discloses another solid-walled implant. This was provided with a fabric coating comprising Dacron velour which was intended to encourage tissue ingrowth.
A development of this implant was disclosed in WO 2007/099500 in which the solid-walled cylindrical body was replaced by an axially outer tubular part spaced from the anchoring section by circumferentially-spaced legs. The tubular part penetrated the skin and formed a ring for connection to a bag or lid. This implant was designed to receive a bowel section drawn up through it; the spaces between the legs allowed the generation of a tissue bond between the inner part of the abdominal wall and the serosal tissue of the bowel in order to provide a more secure, stable, leak-proof and well-vascularised tissue-implant junction. In some embodiments, a circumferential ingrowth mesh was additionally provided. This extended along most of the length of the tubular part with an annular gap being provided between it and the tubular part to facilitate growth of serosal tissue through the mesh.
In a further development, disclosed in WO 2009/024568, the present applicant proposed a cylindrical body formed of two axially-spaced tubular parts. The outer tubular part penetrated the skin and provided a connecting ring. The inner tubular part was attached to an anchoring flange of the type previously described. The two parts were connected together by a “distance means” comprising either radially-spaced legs or a rigid cylindrical ingrowth mesh which allowed for the generation of a tissue bond between the abdominal wall and the bowel. By means of this arrangement, a break was provided in the possible infection path along the implant from the skin.
In a still further development, the applicant disclosed in WO 2010/125346 a percutaneous ostomy implant comprising a cylindrical part for mounting an external detachable device, a cylindrical ingrowth mesh and a circular flange for anchoring the implant. The cylindrical part and circular flange were attached to opposite ends of the ingrowth mesh, with the mesh extending inside the cylindrical part. The implant was configured such that when it is implanted in the abdominal wall of a patient, abdominal tissue including the epidermis meets the ingrowth mesh and is able to attach therethrough directly to serosal tissue of a bowel segment inside the implant. Thus, it was based on the hypothesis that by allowing the epidermis to attach directly to the serosal tissue, bacterial infection (i.e. bacterial attachment to implant surface and subsequent migration) can be prevented.
However, whilst this implant was found to be effective in ensuring sound attachment of the serosal tissue to the abdominal tissue, it had a drawback in that it became more difficult to ensure a fluid-tight seal between the exterior parts of the implant and the bowel segment. This was because the implant relied upon the bowel segment extending within the cylindrical part and maintaining secure infiltration of serosal tissue through the mesh inside that part to form a good seal to the implant. If the bowel receded below the cylindrical part, a leakage path could be formed through the mesh, even if the bowel segment and abdominal wall remained integrated and the implant remained secure and free of infection.
WO 2011/126724 discloses a stoma stabilising device intended to prevent stomas from constricting over time and hence requiring surgical re-opening. The preferred embodiments comprise a flexible mesh tube with a radially extending mesh anchoring flange. In some variants, multiple layers of mesh may be employed.
In WO 2012/131351, the applicant presented further developments relating to percutaneous ostomy implants comprising a connecting member, a first tubular ingrowth member and a second tubular ingrowth member radially outwardly spaced from the first tubular ingrowth member, a radially-extending dermal anchor to engage the abdominal wall beneath the dermis, and/or a tubular ingrowth member arranged around the connecting member. This implant was formed by a laser cutting process.
However, in trials, this implant was still found to have problems. For example, this implant was fixed to the muscle sheath with an anchor provided at the bottom. This was not ideal with patients adding or losing weight since the implant height was fixed and the thickness of a patient's abdomen could vary over time. There was also insufficient ingrowth at the top of the implant. These factors could lead to skin problems, implant overgrowth, excessive implant protrusion and leakage from the system.